Operating Engineers: Fill & Download for Free

Q: If an engine fails on a twin engine airplane (larger commercial airliner), and the pilot accidentally kills the operational engine instead of the faulty one, can it recover?That depends. First, the crew has to recognize the mistake. There are a number of reasons they might not. In one notable case, an air crew shut down the good engine because they misread the symptoms of failure owing to a rerouting of hydraulics in the particular, newer, model aircraft they were flying.Assuming they realize the mistake and want to restart the good engine, it then depends on the aircraft type, altitude, and control. A large commercial turbofan can generally be restarted either using bypass air from a good engine or by diving and using ram air and pinwheeling. The former is not available if both engines are down. The latter only works if they have enough altitude and control to pull it off.Smaller turbo-props sometimes have electric starters, which might be used to restart an engine using power from the APU.If you like science, you might like my free award-winning scifi sampler.

Why can an airplane fly with one of the two engines fail without losing balance?First, let’s make one thing — in two parts — perfectly clear.Pilots that fly twin or multiengine aircraft have separate “Multiengine” pilot’s licenses as differentiated from a single engine pilot’s license.Multiengine pilots, as part of their training to earn the multiengine license and as part of periodic ongoing training, learn to fly with an engine “caged.” That means stopped and not providing any thrust.Like this:The real issue and potential concern when one engine isn’t operating is that the aircraft slows enough that the operating engine overpowers the pilot's ability to control the aircraft.In aviation terms that’s known as a Vmc or Minimum Controllable Airspeed loss of control.How does a pilot keep that from happening?It’s simply a matter of keeping enough airspeed such that the controls have enough authority to control the aircraft.Frankly, it’s not a particularly difficult or dangerous procedure as long as the aircraft maintains or exceeds that critical airspeed. And even that isn’t that much of an issue because, if the pilot begins to lose control authority, the power on the operating engine can be retarded, the aircraft’s nose lowered to increase the airspeed, and the operating engine’s power is once again increased.Many years ago, Piper Aircraft took a Piper Aztec (like pictured above), removed one of the propellers and secured it in the baggage compartment.Then they flew that one propellered twin engined aircraft to demonstrate how safe twin engine aircraft can be when flown properly…Frankly, nobody in their right mind would recommend attempting that again!But it did make the point…

Its 2 am in the night. A group of engineers are looking intently on the monitors in front of them. Their faces, tense. Everything must go according to the procedure. No deviations. No mistakes allowed. The plant is being started, technically called a light up and should be done according to the schedule. The shift in charge is yelling instructions. There is constant ringing of the desk phones. To an outsider it is utter chaos.Power engineers are one of the most underappreciated engineers. Barely anyone outside the industry ever hears of them. The dedication and work they do goes unnoticed.In a power plant there are various departments like operation, Control and Instrumentation, Maintenance, Chemistry etc. A plant runs with the cooperation of all the departments. But it is the operation Department which oversees the day to day running of the plant. Operation engineers work in shifts. There are three shifts including night shifts. That in itself is quite difficult for the human body to adapt. Then there is the matter of responsibility of running huge machines like turbines, pumps and compressors. The biggest pump, for example, in a 600MW unit is a Boiler Feed Pump which is a 12MW machine. That means, it is of the same power as of 150 hatchback cars of 100Horsepower.Also it is equal to the power capacity of 6 locomotive engines. One can imagine the might of this machine and the responsibility attached to running it.With huge machines come maintenance problems. Giving permission, technically called a permit, to other Departments for resolving issues is a very critical task. The permit giver who is an Operation engineer must ensure that the concerned machine is isolated and won’t affect other machines, processes and most importantly the personnel involved in the maintenance. Apart from all these there are hundreds of parameters to keep an eye on. The operation engineer should know the range of these parameters, he/she should know what is an abnormal value, at what value the machine stops (technically called a trip) and at what value it is harmful for the machine.Running a plant of 600MW is no small task. If the plant trips then 600MW is being suddenly removed from the grid. A grid is nothing but a network of power generators and consumers of electricity. So when 600MW is suddenly removed the whole grid is shaken up. So utmost care has to be taken to avoid tripping of a running plant.As can be seen from the above examples Operation Engineers have a very responsible job and it involves split second decision making. They deserve much more recognition than what the society gives them.